Syntax

   FACTORY_DEF <ReaderKeyword> DisplacementFactory
   [FACTORY_NAME <factory name>]
   [INPUT (BASE|CANDIDATE) FEATURE_TYPE <feature type>
      [<attribute name> <attribute value>]*
      [<feature function>]*]*
   [GROUP_BY [<attribute name>]+]*
   STIFFNESS <stiffness>
   MIN_DISTANCE <min distance>
   DISPLACE_ENDPOINTS [(YES|NO)]
   MULTI_BASE (YES|NO|BASES_FIRST)
   [OUTPUT (DISPLACED|UNTOUCHED|INVALID_BASE|INVALID_CANDIDATE|EXTRA_BASE)
      FEATURE_TYPE <feature type>
      [<attribute name> <attribute value>]*
      [<feature function>]*]*

Overview

   This factory is used to resolve proximity conflicts between point, linear and 
   polygonal features, usually after generalization. For example, a road may lie 
   too close to another and we want it displaced in a way that preserves its 
   topology as much as possible. This factory currently uses an adaptation of 
   the Nickerson algorithm.

   The input features may be grouped based on attribute values specified in the 
   GROUP_BY clause.

   The STIFFNESS clause specifies how much the displacement at one point in the 
   candidate feature's geometry should affect the neighboring points. A lower 
   value means that the candidate geometry can be deformed easily while a higher 
   value means that it will try its best to keep its original shape. This 
   floating point value must be greater than 0.

   The MIN_DISTANCE clause specifies the minimum separating distance between the 
   candidate feature's geometry and the base feature's geometry after 
   displacement. This distance must be greater than 0.

   The DISPLACE_ENDPOINTS clause specifies whether or not to displace the 
   endpoints of candidate features whose geometries are unclosed lines.

   The MULTI_BASE clause specifies whether we allow one or more base features 
   per group. Any extra base feature(s) go out through the EXTRA_BASES port. The 
   BASES_FIRST option is an optimization, such that each candidate feature can 
   be processed immediately. If it is specified, user must guarantee that all 
   base feature are passed in before any candidate features. 

Input Tags

   The DisplacementFactory uses the following input tags.
   
   BASE  
   
      Features are geometrically frozen (cannot move). The accepted geometries 
      are point, curve and area.
   
   CANDIDATE   
   
      Features that will be potentially displaced in order to resolve the 
      proximity conflicts with the base feature(s). The accepted geometries are 
      point, line and simple area.

Output Tags

   The DisplacementFactory supports the following output tags.
   
   DISPLACED   
   
      All candidate features that were displaced are output through this port. 
      The geometries of these features are now curves.
   
   UNTOUCHED   
   
      All candidate features that were not displaced are output through this 
      port. These features preserve their original geometry.
   
   INVALID_BASE   
   
      All base features with geometry other than point, curve or area or which 
      for some reason cannot be converted to a line are output with this clause.
   
   INVALID_CANDIDATE 
   
      All candidate features with geometry other than point, curve or simple 
      area or which for some reason cannot be converted to a line are output 
      through this port.
   
   EXTRA_BASE  
   
      If the MULTI_BASE clause is set to no, all extra base features are output 
      through this port.